JP3644919B2 - AC generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an AC generator driven by, for example, an internal combustion engine, and more particularly, to a stator structure of an AC generator for a vehicle mounted on a vehicle such as a passenger car or a truck.
[0002]
[Prior art]
FIG. 19 is a sectional view showing a conventional vehicle alternator, and FIG. 20 is a perspective view showing a stator of a conventional vehicle alternator.
19 and 20, an AC generator for a vehicle is mounted with a Randle-type rotor 7 rotatably in a case 3 composed of an aluminum front bracket 1 and a rear bracket 2 via a shaft 6. The stator 50 is configured to be fixed to the inner wall surface of the case 3 so as to cover the outer peripheral side of the rotor 7.
The shaft 6 is rotatably supported by the front bracket 1 and the rear bracket 2. A pulley 4 is fixed to one end of the shaft 6 so that the rotational torque of the engine can be transmitted to the shaft 6 via a belt (not shown). A slip ring 9 for supplying current to the rotor 7 is fixed to the other end of the shaft 6, and a pair of brushes 10 are accommodated in a brush holder 11 disposed in the case 3 so as to be in sliding contact with the slip ring 9. ing. A regulator 18 that adjusts the magnitude of the AC voltage generated in the stator 50 is bonded to the heat shim 17 fitted to the brush holder 11. A rectifier 12 that is electrically connected to the stator 50 and rectifies alternating current generated in the stator 50 into direct current is mounted in the case 3.
[0003]
The rotor 7 is provided so as to cover the rotor coil 13 that generates a magnetic flux by passing an electric current, and a pair of pole cores 20 in which magnetic poles are formed by the magnetic flux generated by the rotor coil 13. , 21. The pair of pole cores 20 and 21 are made of iron, and each has six claw-shaped claw-shaped magnetic poles 22 and 23 projecting from the outer peripheral edge at an equiangular pitch in the circumferential direction so as to engage the claw-shaped magnetic poles 22 and 23. The shaft 6 is fixed. Further, the fan 5 is fixed to both ends of the rotor 7 in the axial direction.
[0004]
The stator 50 includes a cylindrical stator core 51 in which a plurality of axially extending slots 51a are formed at a predetermined pitch in the circumferential direction, a stator winding 52 wound around the stator core 51, and a stator winding. The insulating resin 25 made of epoxy resin or the like in which the coil ends 52a and 52b on the front side and the rear side of the wire 52 are molded, and the stator winding 52 and the stator core 51 are electrically connected to each slot 51a. And an insulator (not shown) for insulation. Here, 36 slots 51a are formed at equal intervals in the stator core 51 so as to accommodate one set of three-phase AC windings corresponding to the number of magnetic poles (12) of the rotor 7. .
[0005]
In addition, intake holes 1 a and 2 a are provided in the end surfaces of the front bracket 1 and the rear bracket 2 in the axial direction, and exhaust holes 1 b and 2 b are provided on the front shoulders of the stator winding 52 on the outer shoulders of the front bracket 1 and the rear bracket 2. The coil ends 52a and 52b on the side and the rear side are provided opposite to each other in the radial direction.
[0006]
Next, a conventional method for manufacturing the stator 50 will be described with reference to FIGS.
First, a belt-like body having irregularities is produced from a belt-like thin plate made of an SPCC material that is a magnetic material. Then, a predetermined number of the belt-like bodies are laminated, and the outer peripheral portion thereof is laser-welded to produce a rectangular parallelepiped laminated core 55 shown in FIG. On one side of the laminated iron core 55, 36 slots 55a are formed.
Further, a single wire 56 made of a copper wire having a circular cross section with an insulation coating is wound around a predetermined number of times with a three-slot pitch to produce a stator winding group 57A having a flat shape as a whole. The winding start end and the winding end end of the strands 56 constituting the stator winding group 57A are a lead wire 56a and a neutral point lead wire 56b, respectively. Further, a single strand 56 is wound in the same manner to produce stator winding groups 57B and 57C.
Thereafter, the three stator winding groups 57A, 57B, and 57C are overlapped with a shift of one slot pitch as shown in FIG. 22, and inserted into the slot 55a for every three slots, and attached to the laminated core 55. To do. Accordingly, as shown in FIG. 23, the three stator winding groups 57A, 57B, and 57C are attached to the laminated core 55.
Next, the laminated core 55 is bent into a cylindrical shape by a molding device (not shown). Then, both end surfaces of the laminated iron core 55 are brought into contact with each other and laser-welded to obtain a cylindrical stator iron core 51. As a result, as shown in FIG. 24, a stator in which three stator winding groups 57A, 57B, 57C are wound around the stator core 51 is obtained.
Furthermore, the coil ends of the stator winding groups 57A, 57B, 57C are molded with the insulating resin 25, and the stator 50 shown in FIG. 20 is obtained.
[0007]
In the stator 50 thus configured, the neutral point lead wires 56b of the strands 56 constituting the stator winding groups 57A, 57B, and 57C are connected, and the stator winding that is a three-phase AC winding. Line 52 is obtained. These stator winding groups 57A, 57B, and 57C each have a phase difference of 120 degrees, and correspond to the a-phase, b-phase, and c-phase windings of the three-phase AC winding. The lead wires 56a of the strands 56 constituting the stator winding groups 57A, 57B, and 57C are connected to the rectifier 12.
[0008]
In the vehicular AC generator configured as described above, a current is supplied from a battery (not shown) to the rotor coil 13 via the brush 10 and the slip ring 9, and a magnetic flux is generated. By this magnetic flux, the claw-shaped magnetic pole 22 of one pole core 20 is magnetized to the N pole, and the claw-shaped magnetic pole 23 of the other pole core 21 is magnetized to the S pole. On the other hand, the rotational torque of the engine is transmitted to the shaft 6 via the belt and the pulley 4, and the rotor 7 is rotated. Therefore, a rotating magnetic field is applied to the stator winding 52, and an electromotive force is generated in the stator winding 52. The alternating electromotive force is rectified to direct current through the rectifier 12, and the magnitude thereof is adjusted by the regulator 18, and the battery is charged.
[0009]
On the rear side, the rotation of the fan 5 causes the outside air to be sucked in through the intake holes 2a provided facing the heat sink 17 of the rectifier 12 and the heat sink 17 of the regulator 18, respectively, and flows along the shaft 6 shaft. 12 and the regulator 18 are cooled and then bent in the centrifugal direction by the fan 5 to cool the coil end 52b on the rear side of the stator winding 52 and discharged to the outside through the exhaust hole 2b. On the other hand, on the front side, the outside air is sucked in the axial direction from the intake hole 1 a by the rotation of the fan 5, and then bent in the centrifugal direction by the fan 5 to cool the coil end 52 a on the front side of the stator winding 52. The air is discharged outside through the exhaust hole 1b.
[0010]
[Problems to be solved by the invention]
In the conventional stator 50, each of the stator winding groups 57A, 57B, and 57C constituting the stator winding 52 is manufactured by winding one strand 56 into a wave winding at a 3-slot pitch for a predetermined number of times. The outer layer, the intermediate layer, and the inner layer are arranged in the direction so as to be shifted by one slot from each other and wound in the slots 51a every three slots.
Therefore, since the turn portions of the strands 56 constituting the coil end are not aligned with each other in the circumferential direction, it is difficult to mold the coil end uniformly with the insulating resin 25 over the entire circumference. The shape was biased both in the circumferential direction and in the axial direction. As a result, the heat dissipation of the coil end portion including the insulating resin 25 becomes non-uniform, the cooling performance of the stator winding 52 deteriorates, and the temperature rise of the stator winding 52 cannot be suppressed. there were.
In addition, since the turn portions of the strands 56 constituting the coil end are not aligned in the circumferential direction, the strands 56 cannot be wound at a high density, resulting in a problem that a high output cannot be obtained.
In addition, the turn portions of the strands 56 adjacent to each other in the circumferential direction of the stator winding groups 57A and 57C constituting the inner layer and the outer layer are displaced from each other in the radial direction, and the inner peripheral surface and the outer peripheral surface of the insulating resin 25 are As shown in FIG. 20, the surface shape has irregularities in the circumferential direction. As a result, there is a problem that the ventilation resistance is increased, and interference noise is generated between the rotor 7 and the inner peripheral surface of the insulating resin 25 to increase wind noise.
[0011]
In order to solve the above-described problems, the present invention is configured such that a long strand is folded outside the slot on the end face side of the stator core, and the inner layer is formed in the slot depth direction within the slot every predetermined number of slots. A stator winding is formed by a plurality of windings formed so as to alternately take the outer layer and the outer layer, and the rotor facing surface of the insulating resin and the bracket provided so as to cover the coil end It is an object of the present invention to provide an AC generator that can be applied to a vehicle that can form a smooth surface to suppress a rise in temperature of a stator winding and realize high output and low noise.
[0012]
[Means for Solving the Problems]
An AC generator according to the present invention includes a rotor that forms an NS pole along the circumferential direction of rotation, a stator core that is disposed to face the rotor, and a stator winding that is mounted on the stator core. A stator, a bracket that supports the rotor and the stator, and a cooling unit that cools the stator winding by passing cooling air through the bracket in conjunction with the rotation of the rotor. In the alternator, the stator core includes a laminated core in which a plurality of slots extending in the axial direction are formed at a predetermined pitch in the circumferential direction, and the stator winding includes a strand made of a continuous wire, and the stator A plurality of windings that are folded outside the slot on both end surfaces of the iron core and wound so as to alternately take the inner layer and the outer layer in the slot depth direction within the slot every predetermined number of slots; A plurality of windings are a plurality of the above-mentioned strands The winding assembly includes at least one set of winding assemblies formed by folding at the same time. The winding assembly includes linear portions connected by turn portions and arranged at a predetermined slot pitch, and adjacent linear portions are the turn portions. The two strands formed in the pattern shifted so as to alternately take the inner layer and the outer layer in the slot depth direction are shifted from each other by the predetermined slot pitch and the linear portions are arranged to overlap each other. The wire pairs are shifted by one slot pitch and arranged in the same number as the predetermined number of slots, and the wire ends are extended to both sides of both ends of the winding assembly, and the pairs of the straight portions overlapped. Are arranged in the same number of pairs as the total number of the slots at a pitch of 1 slot, and the turn portions of the strands folded back outside the slots on both end surfaces of the stator core are circumferential. And the insulating resin is provided so as to cover the entire coil end, and at least one of the rotor-facing surface and the bracket-facing surface of the insulating resin is formed on a smooth surface. It is what.
[0013]
Further, the rotor facing surface of the insulating resin is formed in a smooth surface, and the bracket facing surface of the insulating resin is in close contact with the inner wall surface of the bracket.
[0014]
Further, in the rotor-facing surface of the insulating resin, at least a part of the surface of the turn portion that is aligned in the circumferential direction that faces the rotor is exposed so as to be in the same plane position as the insulating resin. Is.
[0015]
Further, 2n of the strands are arranged in each of the slots in the slot depth direction, and the turn portions of the strands are arranged in n rows in the circumferential direction.
[0016]
Moreover, the said turn part which comprises the coil end of the at least one edge part of the said stator iron core is formed in the substantially identical shape in the circumferential direction.
[0017]
In addition, at the coil end of at least one end of the stator core, spaces between the turn portions adjacent in the circumferential direction are formed substantially the same.
[0018]
Further, the opening size of the opening of the slot is smaller than the dimension of the element wire in the slot width direction.
The cross-sectional shape of the element wire in the slot is a substantially rectangular shape along the slot shape.
[0020]
Moreover, the cross-sectional shape of the said strand is a substantially flat shape, and the said linear part is accommodated in the said slot along with the cross-sectional longitudinal direction aligned with the radial direction in a line.
[0021]
In addition, at least one of the coil ends of the stator winding is disposed adjacent to the cooling unit on the downstream side in the flow direction of the cooling air formed in the bracket of the cooling unit. .
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
1 is a cross-sectional view showing the configuration of a vehicle alternator according to Embodiment 1 of the present invention, FIG. 2 is a perspective view showing a stator of the vehicle alternator, and FIG. 3 is the vehicle alternator. FIG. 4 is a perspective view illustrating the winding state of the stator winding in the stator of the vehicle alternator, and FIG. 5 is the vehicle. FIG. 6 and FIG. 7 are diagrams for explaining a manufacturing process of a winding assembly constituting a stator winding applied to the vehicular AC generator. FIG. 8 is a view showing a winding assembly on the inner layer side constituting the stator winding applied to the vehicle alternator. FIG. 8 (a) is a side view thereof, and FIG. 8 (b) is a side view thereof. FIG. FIG. 9 is a view showing a winding assembly on the outer layer side constituting a stator winding applied to the vehicle alternator. FIG. 9 (a) is a side view thereof, and FIG. 9 (b) is a side view thereof. FIG. FIG. 10 is a perspective view showing the main part of the wire constituting the stator winding applied to the vehicle alternator, and FIG. 11 constitutes the stator winding applied to the vehicle alternator. It is a figure explaining the arrangement | sequence of a strand. FIG. 12 is a perspective view showing a laminated core constituting the stator core of the vehicle alternator. FIG. 13 is a process sectional view for explaining a stator manufacturing process applied to the vehicle alternator. These are top views which show the mounting state to the laminated iron core of the coil | winding assembly which comprises the stator coil | winding applied to this vehicle AC generator. In FIG. 4, lead wires, neutral point lead wires, and crossover connections are omitted.
[0023]
1 and 2, the pair of pole cores 20 and 21 constituting the rotor 7 are made of iron, and eight claw-shaped claw-shaped magnetic poles 22 and 23 are provided on the outer peripheral edge so as to project at an equiangular pitch in the circumferential direction. The claw-shaped magnetic poles 22 and 23 are fixed to the shaft 6 so as to face each other. In addition, fans 5 as cooling means are fixed to both ends of the rotor 7 in the axial direction.
The stator 8 includes a cylindrical stator core 15 in which a plurality of axially extending slots 15a are formed at a predetermined pitch in the circumferential direction, a stator winding 16 wound around the stator core 15, and a stator winding. An insulating resin 25 made of epoxy resin or the like in which the entire coil ends 16a and 16b on the front side and the rear side of the wire 16 are molded, and the stator winding 16 and the stator core 15 are mounted in each slot 15a. And an insulator 19 (to be described later) that is electrically insulated. In the stator winding 16, one strand 30 is folded outside the slot 15 a on the end face side of the stator core 15, and the inner layer and the outer layer are formed in the slot depth direction in the slot 15 a every predetermined number of slots. And a plurality of windings wound and wound so as to be alternately taken. Here, 96 slots 15a are formed at equal intervals in the stator core 15 so as to accommodate two sets of three-phase AC windings 160, which will be described later, corresponding to the number of magnetic poles (16) of the rotor 7. Has been. In addition, for the strand 30, for example, a long copper wire having a rectangular cross section that is covered with insulation is used.
Other configurations are the same as those of the conventional vehicle alternator shown in FIG.
[0024]
Next, the winding structure of the stator winding group 161 for one phase will be specifically described with reference to FIG.
The stator winding group 161 for one phase is composed of first to fourth windings 31 to 34 each including one strand 30. And the 1st coil | winding 31 is the 1st position from the inner peripheral side in the slot 15a, and the second from the inner peripheral side in every 6 slots from 1 to 91 of the slot number. It is constituted by winding for one turn so as to alternately take positions. The second winding 32 alternates between the second position from the inner circumference side and the first position from the inner circumference side in the slot 15a every six slots from the slot numbers 1 to 91 in the second winding 32. It is constructed by winding one turn so as to take. The third winding 33 alternates between the third position from the inner periphery side and the fourth position from the inner periphery side in the slot 15a every six slots from the slot numbers 1 to 91 in the third winding 33. It is constructed by winding one turn so as to take. The fourth winding 34 alternates between the fourth position from the inner peripheral side and the third position from the inner peripheral side in the slot 15a of the strand 30 every six slots from slot numbers 1 to 91. It is constructed by winding one turn so as to take. In each slot 15a, four strands 30 are arranged in a row in the radial direction with the longitudinal direction of the rectangular cross section aligned in the radial direction.
Hereinafter, the first to fourth positions on the inner peripheral side in the slot 15a in which the wire 30 is accommodated are referred to as addresses 1 to 4, respectively.
[0025]
Then, on one end side of the stator core 15, an end portion 32 a of the second winding 32 extending from the first address of the slot number 1 and a fourth winding extending from the third address of the slot number 91. 34 is joined to the end 34b, and the end 34a of the fourth winding 34 extending from the first slot No. 4 and the second winding extending from the first slot No. 91 The end portion 32b of 32 is joined to form a two-turn winding composed of the second and fourth windings 32 and 24.
Further, on the other end side of the stator core 15, the end 31a of the first winding 31 extending from the first address of the slot number 1 and the third winding extending from the fourth address of the slot number 91 The end 33b of the wire 33 is joined, and the end 33a of the third winding 33 extending from the third slot number 1 and the first winding extending from the second slot number 91 are connected. The end 31 b of the line 31 is joined to form a two-turn winding composed of the first and third windings 31 and 33.
[0026]
Further, the portion of the strand 30 of the third winding 33 extending from the third address of the slot number 61 and the fourth address of the 67 to the one end side of the stator core 15 is cut, and the slot number of the 67th The portion of the wire 30 of the fourth winding 34 extending from the third address and the fourth address 73 to the one end side of the stator core 15 is cut. Then, the cut end 33c of the third winding 33 and the cut end 34c of the fourth winding 34 are joined, and the first to fourth windings 31 to 34 are connected in series for one phase of four turns. A stator winding group 161 is formed.
The junction between the cut end 33c of the third winding 33 and the cut end 34c of the fourth winding 34 becomes a crossover connection, and the cut end 33d of the third winding 33 and the cut end of the fourth winding 34 are connected. 34d becomes the lead wire (O) and the neutral point lead wire (N), respectively.
[0027]
In the stator 8, six-phase stator windings 161 are formed by shifting the slots 15 a around which the strands 30 are wound one by one. The stator windings 161 for these six phases constitute the stator winding 16.
Here, each of the strands 30 constituting the first to fourth windings 31 to 34 extends from one slot 15a to the end face side of the stator core 15 and is folded back into the slot 15a separated by 6 slots. So that it is wound in a wave winding. And each strand 30 is wound so that an inner layer and an outer phase may be taken alternately with respect to the slot depth direction (radial direction) every six slots.
And the turn part 30a of the strand 30 extended to the end surface side of the stator core 15 and turned up forms the coil end. Therefore, at both ends of the stator core 15, as shown in FIG. 4, the turn portions 30a formed in substantially the same shape are spaced apart from each other in the circumferential direction and in the radial direction to form two rows in the circumferential direction. The coil ends 16a and 16b are arranged in an orderly manner.
[0028]
Next, the stator 8 shown in FIG. 2 is obtained by molding so as to completely cover the entire coil ends 16 a and 16 b of the stator winding 16 with the insulating resin 25. At this time, the insulating resin 25 is molded so as not to cause unevenness on the surface due to the discontinuous state in the circumferential direction in which the turn portions 30a are arranged with a predetermined gap. That is, the rotor facing surface 25a that is the inner peripheral surface of the insulating resin 25 and the bracket facing surface 25b that is the outer peripheral surface are formed on smooth surfaces. The stator 8 configured in this manner is mounted on an AC generator for a vehicle, and as shown in FIG. 5, the stator winding group 161 is star-connected in three phases and two sets of three-phase alternating currents. A winding 160 is formed, and each three-phase AC winding 160 is connected to the rectifier 12. Then, the DC outputs of the rectifiers 12 are connected in parallel and combined.
[0029]
Next, a method for manufacturing the stator 8 will be specifically described with reference to FIGS.
First, as shown in FIG. 6, twelve long strands 30 are simultaneously bent into a lightning shape on the same plane. Next, as shown by the arrows in FIG. 7, it is folded with a jig in a right angle direction to produce the inner layer side winding assembly 35A shown in FIG. Further, similarly, as shown in FIG. 9, a winding assembly 35B on the outer layer side having a cross connection, a neutral point lead wire, and a lead wire is produced.
As shown in FIG. 10, each element wire 30 is formed by bending into a planar pattern in which straight portions 30b connected by a turn portion 30a are arranged at a 6-slot pitch (6P). And the adjacent linear part 30b is shifted by the width (W) of the strand 30 by the turn part 30a. In the winding assemblies 35A and 35B, two strands 30 formed in such a pattern are shifted by 6 slots as shown in FIG. 11, and a pair of strands arranged by overlapping the straight portions 30b is 1 slot. Six pairs are arranged by shifting the pitch. And the end part of the strand 30 is extended 6 each on both sides of the both ends of winding assembly 35A, 35B. Further, the turn part 30a is aligned and arranged on both sides of the winding assemblies 35A and 35B.
Further, a predetermined number of SPCC materials in which trapezoidal slots 36a are formed at a predetermined pitch (electrical angle of 30 °) are stacked, and the outer periphery thereof is laser-welded, as shown in FIG. An iron core 36 is produced.
[0030]
Then, as shown in FIG. 13A, the insulator 19 is mounted in the slot 36a of the laminated core 36, and the straight portions of the two winding assemblies 35A and 35B are overlapped and pushed into the slots 36a. Thereby, as shown in FIG. 13B, the two winding assemblies 35 </ b> A and 35 </ b> B are attached to the laminated iron core 36. At this time, four straight portions 30b of the strands 30 are insulated from the laminated iron core 36 by the insulator 19, and are accommodated in the slots 36a side by side in the radial direction. Further, as shown in FIG. 14, the two winding assemblies 35 </ b> A and 35 </ b> B are overlapped and attached to the laminated core 36.
Next, the laminated iron core 36 is rounded, its end faces are brought into contact with each other and laser-welded, and a cylindrical stator core 15 is obtained as shown in FIG. By rounding the laminated core 36, the slot 36a (corresponding to the slot 15a of the stator core 15) has a substantially rectangular cross-sectional shape, and its opening 36b (corresponding to the opening 15b of the slot 15a) is in the slot width direction of the linear portion 30b. Smaller than dimensions. And based on the connection method shown by FIG. 3, the edge part of each strand 30 is connected, and the stator winding group 161 is formed. Furthermore, the insulating resin 25 is molded so as to cover the entire coil ends 16a and 16b of the stator winding 16.
[0031]
Thus, according to the first embodiment, since the insulating resin 25 is molded so as to cover the entire coil ends 16a and 16b, the insulating properties of the coil end portions are ensured and they are adjacent by vibration. The turn portions 30a come into contact with each other to damage the insulating coating, and the reliability can be improved without causing a short circuit accident. Further, the rigidity of the stator 8 can be increased, and magnetic noise can be reduced.
Further, since the rotor facing surface 25a of the insulating resin 25 is formed to be a smooth surface, the ventilation resistance of the cooling air flowing between the insulating resin 25 and the rotor 7 is reduced, and the insulating resin The interference noise between the rotor 25 and the rotor 7 is reduced, and wind noise can be reduced.
Further, since the bracket facing surface 25b of the insulating resin 25 is formed on a smooth surface, the ventilation resistance of the cooling air flowing between the insulating resin 25 and the brackets 1 and 2 is reduced, and wind noise is reduced. can do.
[0032]
The stator winding 16 includes two sets of three-phase AC windings 160, and each three-phase AC winding 160 is configured by AC-connecting a three-phase stator winding group 161. The stator winding group 161 is configured by connecting first to fourth windings 31 to 34 in series. The first winding 31 is formed by winding a single wire 30 every six slots so as to alternately take the first address and the second address in the slot 15a. That is, the first winding 31 is formed by winding one strand 30 for every six slots so that the inner layer and the outer layer are alternately taken in the slot depth direction in the slot 15a. Similarly, the second, third, and fourth windings 32, 33, 34 are also configured so that one strand 30 of the inner layer and the outer layer are alternately arranged in the slot depth direction in the slot 15a every six slots. It is configured to be wound by one turn.
Therefore, the turn portions 30a of the strands 30 constituting the first and second windings 31 and 32 can be formed in substantially the same shape, and the turn portions 30a can be aligned and aligned in the circumferential direction. Similarly, the turn portion 30a of the strand 30 constituting the third and fourth windings 33 and 34 can be formed in substantially the same shape, and the turn portion 30a is surrounded on the outer peripheral side of the first and second windings 31 and 32. Can be aligned and aligned in the direction. That is, the turn portions 30a have substantially the same shape in the circumferential direction, and the gaps between the turn portions 30a are substantially the same in the circumferential direction.
By adopting this winding structure, it becomes easy to uniformly mold the coil ends 16a and 16b over the entire circumference with the insulating resin 25, and the distribution in the circumferential direction and the axial direction of the insulating resin 25 is almost uniform. Can be formed. Thereby, the heat dissipation of the coil end portion including the insulating resin 25 becomes uniform, deterioration of the cooling performance of the stator winding 16 is suppressed, and the temperature rise of the stator winding 16 can be suppressed.
Further, by adopting this winding structure, the rotor facing surface 25a and the bracket facing surface 25b of the insulating resin 25 can be easily formed on smooth surfaces.
Further, by adopting this winding structure, it becomes possible to increase the density of the strands 30 and improve the output, and the amount of the insulating resin 25 can be reduced as compared with the conventional stator 50. Pricing is planned.
[0033]
Four strands 30 are arranged in a row in the radial direction in the slot 15a, and the turn portions 30a are arranged in two rows in the circumferential direction. Thereby, since the turn parts 30a constituting the coil ends 16a and 16b are respectively distributed in two rows in the radial direction, the extension height of the coil ends 16a and 16b from the end face of the stator core 15 can be lowered. As a result, the height of the insulating resin 25 in which the coil ends 16 a and 16 b are molded can be lowered, the ventilation resistance in the insulating resin 25 is reduced, and wind noise caused by the rotation of the rotor 7 can be reduced. In addition, the coil end leakage reactance at the coil end is reduced, and the output and efficiency are improved.
In addition, since the coil ends 16a and 16b are disposed adjacent to the fan 5 on the downstream side of the fan 5, the cooling air flowing into the ventilation path by the fan 5 efficiently molds the coil ends 16a and 16b. The cooling of the stator winding 16 can be improved by being used for cooling the conductive resin 25.
[0034]
Further, the number of magnetic poles of the rotor 7 is 16, and 96 slots 15a are formed in the stator core 15 at an equiangular pitch. Since the winding 30 is wound in the slots 15a every six slots, the pitch of the slots in which the winding 30 is wound becomes a pitch corresponding to the NS pole of the rotor 7, and the stator winding 16 is All node windings. As a result, the maximum torque can be obtained and high output can be realized.
Further, since the opening dimension of the opening 15b of the slot 15a is smaller than the dimension of the element wire 30 in the slot width direction, the element wire 30 is prevented from jumping out radially inward from the slot 15a and the opening 15b. The interference sound with the rotor 7 at is also reduced.
[0035]
Moreover, since the straight part 30b is formed in the rectangular cross section, when the straight part 30b is accommodated in the slot 15a, the cross-sectional shape of the straight part 30b becomes a shape along the slot shape. Thereby, it becomes easy to raise the space factor of the strand 30 in the slot 15a, and the heat transfer from the strand 30 to the stator core 15 can be improved. Here, in the first embodiment, the straight portion 30b is formed in a rectangular cross section. However, if the cross sectional shape of the straight portion 30b is a substantially rectangular cross sectional shape along the slot shape of the substantially rectangular cross section. Good. The substantially rectangular shape is not limited to a rectangle, and may be a square shape, a shape formed by four sides and a rounded corner, an oval shape having a short side of the rectangle as an arc, or the like.
[0036]
Moreover, since the strand 30 is formed in the rectangular cross-sectional shape, the thermal radiation area from the turn part 30b which comprises a coil end becomes large, and the heat_generation | fever of the stator winding | coil 16 is efficiently thermally radiated.
[0037]
In addition, as shown in FIG. 5, the stator winding group 161 configured by connecting the first to fourth windings 31 to 34 in series is connected in a star-shaped manner to form two sets of three-phase alternating currents. The winding 160 is configured, and two sets of three-phase AC windings 160 are connected to the rectifier 12, and the outputs of the two rectifiers 12 are connected in parallel. As a result, the DC output of the four-turn three-phase AC winding 160 can be synthesized and taken out, and power generation shortage in the low rotation range can be resolved.
[0038]
Further, when the number of turns of the stator winding is increased by adopting this winding structure, the winding assemblies 35 (35A, 35B) made of continuous lines are overlapped so that the straight portions 30b are aligned with each other. And it can respond easily by winding around the stator core 15.
In addition, the stator 8 according to the first embodiment is manufactured by inserting a winding assembly 35 made of a continuous wire into a slot 36a of a rectangular parallelepiped laminated core 36 through an opening 36b, and then rounding the laminated core 36 into an annular shape. Can do. Therefore, since the opening dimension of the opening 36b of the laminated core 36 can be made larger than the slot width method dimension of the strand 30, the workability of inserting the winding assembly 35 can be improved. Moreover, since the opening dimension of the opening part 36b can be made smaller than the slot width method dimension of the strand 30 by shape | molding the lamination | stacking iron core 36 in cyclic | annular form, a space factor can be raised and an output can be improved. Furthermore, even if the number of slots increases, the productivity of the stator does not decrease.
[0039]
Further, since both the coil ends 16a and 16b (insulating resin 25 in which the coil ends 16a and 16b are molded) are substantially equal and the fan 5 is provided at both ends of the rotor 7, both the coil ends 16a 16b are cooled in a well-balanced manner, and the stator winding temperature is uniformly and greatly reduced.
Here, the fans 5 do not necessarily have to be provided at both ends of the rotor 7, and may be provided in consideration of the arrangement positions of the stator windings and rectifiers which are large heating elements. For example, the coil end of the stator winding, which is the largest heating element, may be disposed on the discharge side of the fan having a high cooling rate, and the fan may be disposed on the end of the rotor on the side where the rectifier is disposed. . Further, when attached to the vehicle engine, the pulley is usually connected to the crankshaft via a belt, so that the fan is preferably arranged on the side opposite to the pulley so that the cooling and exhausting air of the fan does not affect the belt. Note that the mold part of the claw-shaped magnetic pole of the rotor also has a blowing action and can be used as a cooling means.
[0040]
Further, since the axial length of the stator 8 including the insulating resin 25 is smaller than the axial length of the pole cores 20 and 21, it is possible to reduce the size. Further, when the fans 5 are provided at both ends of the rotor 7, since the insulating resin 25 is not provided on the fan discharge side, the ventilation resistance is remarkably reduced, wind noise is reduced, and the rectifier 12 and the like are cooled. The temperature rise of built-in objects can be suppressed.
[0041]
Further, the number of slots in which the stator windings 16 are accommodated is 2 per pole per phase, and there are two three-phase AC windings 160 corresponding to the slots per pole per phase. Thereby, a magnetomotive force waveform can be made close to a sine waveform, a harmonic component can be reduced, and a stable output can be obtained. Further, since the number of slots 15a is increased, the teeth of the stator core 15 are thinned, magnetic leakage in the teeth between the claw-shaped magnetic poles 22 and 23 facing each other is reduced, and output pulsation can be suppressed. Further, as the number of slots 15a increases, the number of turn portions 30a increases corresponding to the slots 15a, so that the heat dissipation of the coil end is improved.
In addition, since the slots 15a and the openings 15b are arranged at an equal interval of 30 ° in electrical angle, magnetic pulsations that cause the excitation force of magnetic noise can be reduced.
[0042]
Embodiment 2. FIG.
In the second embodiment, as shown in FIG. 15, the stator 8 is disposed such that the bracket facing surface 25 b of the insulating resin 25 is in close contact with the inner wall surfaces of the front and rear brackets 1 and 2. It is. Other configurations are the same as those in the first embodiment.
[0043]
According to the second embodiment, since the bracket facing surface 25b of the insulating resin 25 is disposed so as to be in close contact with the inner wall surfaces of the brackets 1 and 2, the heat generated in the coil ends 16a and 16b is insulated. It is efficiently transmitted to the low-temperature brackets 1 and 2 through the resin 25, so that the cooling performance of the stator winding 16 can be improved and there is no gap between the insulating resin 25 and the inner wall surfaces of the brackets 1 and 2. The AC generator can be reduced in size.
[0044]
Embodiment 3 FIG.
In the third embodiment, as shown in FIG. 16, a part of the outer peripheral surface (the surface facing the rotor 7) of the turn portion 30 a of the strand 30 constituting the inner layer side is a rotor having an insulating resin 25. It is exposed so as to be in the same plane position as the facing surface 25a. Other configurations are the same as those in the first embodiment.
[0045]
According to the third embodiment, since the cooling air strikes the exposed surface of the turn portion 30a of the strand 30, the heat generated in the coil ends 16a and 16b is efficiently radiated from the exposed surface of the turn portion 30a, and the stator winding The cooling performance of the wire 16 can be improved.
Here, if the strand 30 is formed in a rectangular cross section, it is easy to define one surface exposed to the rotor facing surface 25a of the insulating resin 25. However, even if the strand is a circular cross section, The same effect can be obtained if a part of the side surface is exposed.
[0046]
In the third embodiment, the surface of the turn portion 30a of the strand 30 constituting the inner layer side that faces the rotor 7 is exposed so as to be flush with the rotor facing surface 25a of the insulating resin 25. However, the outer peripheral surface (the surface facing the brackets 1 and 2) of the turn portion 30a of the strand 30 constituting the outer layer side is flush with the bracket facing surface 25b of the insulating resin 25. It may be exposed.
[0047]
Embodiment 4 FIG.
In the fourth embodiment, as shown in FIG. 17, the slots 150a of the stator core 150 are formed at an equiangular pitch, and the circumferential gap center of the slot opening 150b is an electrical angle (α °) and (60 It is assumed that they are formed at unequal intervals that alternately repeat -α) °. Here, α ≠ 30. Other configurations are the same as those in the first embodiment.
[0048]
According to the fourth embodiment, the interval between the circumferential gap centers of the slot openings 150b is formed at unequal intervals that alternately repeat (α °) and (60−α) ° in electrical angle. The two sets of three-phase AC windings 160 are wound with a phase difference of (60−α) ° in electrical angle. Here, FIG. 18 shows the results of measuring changes in each order component of the stator magnetomotive force harmonics that cause the magnetic noise by mounting the stator with different α on the AC generator. Note that α is changed by adjusting the circumferential length of the flange portion 150d provided at the tip of the tooth portion 150c.
From FIG. 18, if the interval between the circumferential gap centers of the slot opening 150b is in a range of unequal intervals repeating 16 degrees and 44 degrees and unequal intervals repeating 29 degrees and 31 degrees, the stator It can be seen that the upper limit value of the fifth, seventh, eleventh and thirteenth magnetomotive force harmonics is suppressed to 13% or less.
Further, if the interval between the circumferential gap centers of the slot opening 150b is in a range of unequal intervals repeating 22 degrees and 38 degrees and unequal intervals repeating 24 degrees and 36 degrees, the stator 5 It can be seen that the upper limit value of the second, seventh, eleventh and thirteenth magnetomotive force harmonics is suppressed to 8% or less, that is, the fifth, seventh, eleventh and thirteenth magnetomotive force harmonics can be reduced in a balanced manner. .
[0049]
In each of the above-described embodiments, an epoxy resin is used as the insulating resin 25. However, as the insulating resin, a material mixed with a member having higher thermal conductivity than the main resin material may be used. For example, an insulating resin obtained by mixing epoxy resin (main agent) having a thermal conductivity of 0.5 (W / mk) and alumina having a thermal conductivity of 3.5 (W / mk) in a ratio of 1: 4. It may be used as In this case, the heat generated in the stator winding 16 is quickly conducted through the insulating resin, reaches the surface of the insulating resin, and is dissipated from the surface of the insulating resin. Can be improved.
In each of the above embodiments, the fan 5 is disposed in the case 3. However, the fan may be provided outside the vehicle AC generator so as to rotate along with the rotation of the rotor. Good.
Further, in each of the above embodiments, the case where the stator winding 161 of each phase has four turns has been described, but the number of turns of the stator winding 161 is not limited to four turns. If further low-speed output is required, the stator winding 161 may be 6 turns or 8 turns. Even in this case, the winding assembly can be dealt with only by overlapping in the radial direction and inserting it into the stator core. Of course, an odd number of turns may be used.
Moreover, although each said embodiment demonstrated as applying to a full-pitch winding generator, you may apply this structure to a short-pitch (not full-pitch winding) generator.
The present invention can also be applied to an AC generator for a vehicle in which a rotor coil is fixed to a bracket and a rotating field is supplied from an air gap.
In each of the above embodiments, the number of stator slots is 96 with respect to the number of magnetic poles of 16 poles. However, with respect to the number of magnetic poles of 12 poles, 72 slots in 3 phases, 20 poles For the number of magnetic poles, 120 slots of three phases may be employed. In the case of 1 per phase per pole, the number of magnetic poles of 16 poles may be 48 slots, the number of magnetic poles of 12 poles may be 36 slots, and the number of magnetic poles of 20 poles may be 60 slots.
In each of the above embodiments, the axial length of the stator including the coil end is configured to be smaller than the axial length of the rotor. This may be applied to a generator in which the axial length of is larger than the axial length of the rotor. In this case, since the coil end exists on the fan discharge side, the temperature rise of the stator can be suppressed.
[0050]
In each of the above embodiments, a Landel type rotor having a claw-shaped magnetic pole is used. However, the same effect can be obtained even if a Selent type rotor having a salient pole type magnetic pole is used.
In each of the above embodiments, the rectifier is arranged on the side opposite to the pulley, and the fan is also arranged on the same side with respect to the rotor. However, if there is no particular problem with the temperature of the rectifier, the fan is arranged on the pulley side. It may be arranged. Since the height of the stator coil ends is low, the ventilation resistance on the discharge side in the fan ventilation path is significantly reduced, so the total air volume increases. Therefore, the positional relationship between the rectifier or pulley and the fan may be selected in consideration of the mounting position of the engine, wind noise, magnetic noise, and the temperature state of each part.
Further, in each of the above embodiments, when the winding assembly is inserted into the laminated iron core, the insulator is inserted in advance on the laminated iron core side. You may make it insert. Further, the insulator may be accommodated in the slot at the same time by placing a long insulator on a rectangular parallelepiped laminated iron core and inserting a winding assembly thereon. In this case, the protruding insulator may be removed at a time in a later step. Further, the slot accommodating portion of the winding assembly may be molded in advance with an insulating resin. In this case, mass productivity is greatly improved.
[0051]
【The invention's effect】
Since this invention is comprised as mentioned above, there exists an effect as described below.
[0052]
According to the present invention, a rotor having NS poles along the circumferential direction of rotation, a stator core disposed opposite to the rotor, and a stator having a stator winding mounted on the stator core, An AC generator comprising: a bracket that supports the rotor and the stator; and a cooling unit that cools the stator winding by passing cooling air through the bracket in conjunction with the rotation of the rotor. The stator core includes a laminated core in which a plurality of slots extending in the axial direction are formed at a predetermined pitch in the circumferential direction, and the stator winding includes a strand formed of a continuous wire at both ends of the stator core. A plurality of windings which are folded back outside the slot on the surface side and wound so as to alternately take an inner layer and an outer layer in the slot depth direction within the slot every predetermined number of slots, Fold multiple strands at the same time. The winding assembly is composed of at least one pair of winding assemblies formed by folding, and the winding assemblies are arranged at a predetermined slot pitch with straight portions connected by turn portions, and adjacent straight portions are arranged by the turn portions. A strand formed by arranging the two straight wires formed in a pattern shifted so as to alternately take the inner layer and the outer layer in the slot depth direction, with the straight portions overlapped with the predetermined slot pitch shifted from each other. The pairs are shifted by one slot pitch and arranged in the same number as the predetermined number of slots. The ends of the strands are respectively extended on both sides of both ends of the winding assembly. The same number of pairs as the total number of the slots are arranged at one slot pitch, and the turn portions of the strands folded back outside the slots on both end surfaces of the stator core are arranged in the circumferential direction. Configure Iruendo, insulating resin is provided so as to cover the entire of the coil end, at least one of the rotor facing surface and the bracket opposite surfaces of the insulating resin is formed into a smooth surface. As a result, the strands can be wound with high density, the output is improved, the heat dissipation of the insulating resin is uniform in the circumferential direction, the cooling performance of the stator winding is improved, and the insulating resin An alternating current generator in which wind resistance of cooling air flowing through the rotor facing surface and the bracket facing surface is reduced and wind noise is reduced is obtained.
[0053]
Further, the rotor facing surface of the insulating resin is formed in a smooth surface, and the bracket facing surface of the insulating resin is in close contact with the inner wall surface of the bracket. Thereby, since the interference sound generated between the insulating resin and the rotor is reduced, the wind noise is reduced and the heat of the stator winding is transmitted to the low temperature bracket via the insulating resin. Therefore, the temperature rise of the stator winding can be suppressed.
[0054]
Further, in the rotor-facing surface of the insulating resin, at least a part of the surface of the turn portion that is aligned in the circumferential direction that faces the rotor is exposed so as to be in the same plane position as the insulating resin. Therefore, the exposed surface of the turn portion is exposed to the cooling air, and the cooling performance of the stator winding can be improved.
[0055]
Further, 2n strands are arranged in each slot in the slot depth direction, and the turn portions of the strands are arranged in n rows in the circumferential direction. Thereby, since the coil end height is lowered, the coil end leakage reactance is reduced, the height of the insulating resin is lowered, and the ventilation resistance is reduced.
[0056]
In addition, since the turn portion constituting the coil end of at least one end of the stator core is formed in substantially the same shape in the circumferential direction, the insulating resin can be provided uniformly on the coil end, The rotor-facing surface and the bracket-facing surface of the insulating resin can be easily formed on a smooth surface.
[0057]
In addition, since the space between the turn parts adjacent in the circumferential direction is formed substantially the same at the coil end of at least one end of the stator core, the insulating resin can be provided uniformly at the coil end. In addition, the rotor-facing surface and the bracket-facing surface of the insulating resin can be easily formed on a smooth surface. Furthermore, the pressure applied during resin molding is uniform, and the turn portions do not interfere with each other due to the pressure.
[0058]
In addition, since the opening dimension of the opening of the slot is smaller than the dimension of the element wire in the slot width direction, jumping out of the element wire from the slot is prevented, and the insulating resin flowing into the slot leaks from the opening. It becomes difficult to put out.
[0059]
Further, since the cross-sectional shape of the wire in the slot is a substantially rectangular shape along the slot shape, the space factor of the wire in the slot is increased, and the output and efficiency are improved. In addition, the contact area between the wire and the stator core is increased, the thermal conductivity is increased, and the temperature of the stator winding is further reduced. Furthermore, it becomes difficult for the insulating resin to flow into the slot, and the amount of resin can be reduced.
[0060]
In addition, since the cross-sectional shape of the strand is substantially flat, and the straight portion is stored in the slot in a line with the longitudinal direction of the cross-section aligned with the radial direction, the strand of the strand in the slot The space factor is increased, the heat dissipation of the stator winding is improved, and the output and efficiency are improved. Furthermore, a smooth resin surface can be easily formed.
[0061]
Further, since the coil end of at least one of the stator windings is disposed adjacent to the cooling means on the downstream side in the flow direction of the cooling air formed in the bracket of the cooling means. The wind is efficiently used for cooling the coil end or the insulating resin, and the cooling performance of the stator winding can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of an automotive alternator according to Embodiment 1 of the present invention.
FIG. 2 is a perspective view showing a stator of the automotive alternator according to Embodiment 1 of the present invention.
FIG. 3 is a plan view illustrating a connection state for one phase of a stator winding in the automotive alternator according to Embodiment 1 of the present invention;
FIG. 4 is a perspective view for explaining a connection state of stator windings in the automotive alternator according to Embodiment 1 of the present invention;
FIG. 5 is a circuit diagram of an automotive alternator according to Embodiment 1 of the present invention.
6 is a diagram illustrating a manufacturing process of a winding assembly that constitutes a stator winding that is applied to the automotive alternator according to Embodiment 1 of the present invention; FIG.
FIG. 7 is a diagram illustrating a manufacturing process of a winding assembly that constitutes a stator winding applied to an automotive alternator according to Embodiment 1 of the present invention;
FIG. 8 is a diagram showing a winding assembly on the inner layer side constituting a stator winding applied to the vehicle alternator according to Embodiment 1 of the present invention;
FIG. 9 is a view showing a winding assembly on the outer layer side that constitutes a stator winding applied to the automotive alternator according to Embodiment 1 of the present invention;
FIG. 10 is a perspective view showing a main part of a wire constituting the stator winding applied to the vehicle alternator according to Embodiment 1 of the present invention;
FIG. 11 is a diagram illustrating an arrangement of strands constituting a stator winding applied to the vehicle AC generator according to Embodiment 1 of the present invention.
FIG. 12 is a perspective view showing a laminated iron core constituting a stator iron core applied to this vehicular AC generator.
FIG. 13 is a process cross-sectional view illustrating a manufacturing process of a stator applied to the vehicle alternator.
FIG. 14 is a plan view showing a state in which a winding assembly constituting a stator winding applied to the vehicle AC generator is mounted on a laminated core.
FIG. 15 is a cross-sectional view of a main part showing an automotive alternator according to Embodiment 2 of the present invention.
FIG. 16 is a perspective view showing a stator of an automotive alternator according to Embodiment 3 of the present invention.
FIG. 17 is a perspective view showing a stator core of a vehicle alternator according to Embodiment 4 of the present invention;
FIG. 18 is a graph showing output characteristics of the automotive alternator according to Embodiment 4 of the present invention.
FIG. 19 is a cross-sectional view showing a conventional vehicular AC generator.
FIG. 20 is a perspective view showing a stator of a conventional vehicle alternator.
FIG. 21 is a perspective view showing a laminated core constituting a stator core applied to a stator of a conventional vehicle alternator.
FIG. 22 is a perspective view illustrating a manufacturing process of a stator applied to a conventional vehicle alternator.
FIG. 23 is a perspective view illustrating a manufacturing process of a stator applied to a conventional vehicle alternator.
FIG. 24 is a perspective view showing a state of a stator applied to a conventional vehicle alternator before an insulating resin mold.
[Explanation of symbols]
1 Front bracket, 2 Rear bracket, 5 Fan (cooling means), 7 Rotor, 8 Stator, 15, 150 Stator core, 15a, 150a Slot, 15b, 150b Opening, 16 Stator winding, 16a Front side Coil end, 16b rear coil end, 25 insulating resin, 25a rotor facing surface, 25b bracket facing surface, 30 strand, 30a turn part, 31 first winding, 32 second winding, 33 third Winding, 34 Fourth winding, 35A, 35B Winding assembly.

Claims (10)

A rotor that forms an NS pole along the circumferential direction of rotation, a stator core that is disposed opposite to the rotor, a stator having a stator winding mounted on the stator core, the rotor and the stator In an AC generator comprising: a bracket that supports a child; and a cooling means that cools the stator winding by passing cooling air through the bracket in conjunction with rotation of the rotor.
The stator core includes a laminated core in which a plurality of slots extending in the axial direction are formed at a predetermined pitch in the circumferential direction,
In the stator winding, a continuous wire is folded outside the slot on both end sides of the stator core, and an inner layer and an outer layer are formed in the slot depth direction in the slot every predetermined number of slots. Have multiple windings wound alternately
The plurality of windings are constituted by at least one set of winding assemblies formed by simultaneously folding a plurality of the wires.
In the winding assembly, linear portions are connected by turn portions and arranged at a predetermined slot pitch, and adjacent linear portions are shifted by the turn portions so that inner layers and outer layers are alternately taken in the slot depth direction. A pair of strands formed by arranging the two strands formed in the pattern so as to be shifted from each other by the predetermined slot pitch and overlaying the linear portions are shifted by one slot pitch and the same number as the predetermined number of slots. The wire ends are extended to both sides of the both ends of the winding assembly, and the pairs of the straight portions overlapped are arranged in the same number as the total number of the slots at one slot pitch. ,
The turns of the strands folded back outside the slot on both end surfaces of the stator core are arranged in the circumferential direction to constitute a coil end,
Insulating resin is provided so as to cover the entire coil end,
An alternator characterized in that at least one of a rotor-facing surface and a bracket-facing surface of the insulating resin is formed on a smooth surface. 2. The AC generator according to claim 1, wherein the rotor-facing surface of the insulating resin is formed into a smooth surface, and the bracket-facing surface of the insulating resin is in close contact with the inner wall surface of the bracket. In the rotor-facing surface of the insulating resin, at least a part of the surface of the turn portion that is aligned in the circumferential direction facing the rotor is exposed so as to be in the same plane position as the insulating resin. The AC generator according to claim 1 or 2, wherein the AC generator is characterized. 2. The device according to claim 1, wherein 2n of the strands are arranged in each of the slots in the slot depth direction, and turn portions of the strands are arranged in n rows in the circumferential direction. 4. The AC generator according to any one of 3. The said turn part which comprises the coil end of the at least one edge part of the said stator core is formed in the substantially same shape in the circumferential direction, The Claim 1 thru | or 4 characterized by the above-mentioned. Alternator. The space between the turn parts adjacent in the circumferential direction is formed substantially the same at the coil end of at least one end of the stator core. The described alternator. The AC generator according to any one of claims 1 to 6, wherein an opening size of the opening of the slot is smaller than a size of the element wire in the slot width direction. The AC generator according to any one of claims 1 to 7, wherein a cross-sectional shape of the element wire in the slot is a substantially rectangular shape along the slot shape. The cross-sectional shape of the strand is substantially flat, and the straight portions are housed in the slots in a line with the longitudinal direction of the cross-section aligned with the radial direction. Item 9. The AC generator according to any one of Items 8. The coil end of at least one of the stator windings is disposed adjacent to the cooling means on the downstream side in the flow direction of the cooling air formed in the bracket of the cooling means. The AC generator according to any one of claims 1 to 9.

Images